When you’re prowling the rows of vendors at the farmer’s market, you probably see a growing number of organic fruits and veggies for sale. Even at the farmers market, organic produce can carry a slightly higher price tag, and you may wonder whether it’s really worth the extra pennies. Here’s more evidence that it just might be: a new study shows that it might be a lot more nutritious.
The findings came out of what is believed to be the largest meta-analysis of this sort to date, using data from nearly 350 peer-reviewed studies to look at the difference in composition between organic and conventionally grown fruits, vegetables, and grains. The international researchers, led by the British Newcastle University, mostly looked at studies covering crops grown in the same area and on similar soil. The researchers referred to the data as “overwhelming” and said that choosing foods with an organic label can deliver “substantially higher” amounts of antioxidants — including 59% more anthocyanins, which we discussed earlier this month — with the added bonus of reducing your intake of bad-for-you heavy metals like cadmium.
Standards for “organic” labels vary by country, but in general, organically grown crops are those grown without synthetic chemicals or certain mineral fertilizers like potassium chloride. Organic farmers use fertilizers like manure and compost, rotate legume crops in order to increase nitrogen (important plant food!) in the soil, and use other non-chemical ways to grow fruits, vegetables, and grains.
What did the researchers find?
- Switching to organically grown crop foods and foods made from organic crops gives you an antioxidant boost equal to 1-2 extra fruit and vegetable servings each day.
- The levels of cadmium, a toxic heavy metal, were almost 50 percent lower in organic crops than in those that were conventionally grown.
- Conventional crops were four times more likely to have pesticide residue than organics.
- There were no significant differences in the amount of protein, carbohydrates, or fiber found in organic vs conventional produce.
Two earlier studies found that organic and conventional crops didn’t have any nutritional or compositional differences. One study from 2009 found that organic food had no nutritional superiority, and another study review from 2012 reported that the only possible difference was minimal evidence of higher phenol levels in organic produce.
But the researchers for the newest study, published in British Journal of Nutrition, said that their review had the benefit of a wider and higher-quality pool of research to investigate. For example, more than half of the studies included in the 2014 analysis weren’t available to the researchers of the 2009 review. It’s important to remember, however, that this new study is both a review of existing research—not new research itself—and looks only at the differences in the composition of organic and conventional crops.
The researchers themselves say that their findings indicate that it’s time for well-controlled studies in humans to investigate how those compositional differences might play out as nutritional differences when eating organic food versus non-organic.
Baranski Marcin et al. Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses. British Journal of Nutrition. 2014;111(12):1-18. doi: 10.1017/S000711451001366.
Terri Coles is a writer and editor living with her family in St. John’s, Newfoundland. When she’s not reporting lifestyle stories, she spends her time watching comedy shows, reading, drinking tea, and staring at the ocean.